On June 8, 2021, about 1600 eastern daylight time, an experimental amateur-built ZODIAC 601 XL, N315SV was substantially damaged when it was involved in an accident near Mexico Farms Airport (1W3), Cumberland, Maryland. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The non-certificated pilot, who was also the owner/builder of the airplane, departed 1W3 for a local flight. According to the pilot at an altitude of 1,000 ft mean sea level while on the base leg in the airport traffic pattern, the cockpit canopy opened in flight. The right side of the canopy detached followed rapidly by the left side, which resulted in the canopy “popping open.” The force of the canopy opening threw the pilot up against his harness as the airplane immediately slowed and descended. The pilot, unable to close the canopy, added full power and attempted to maintain level flight but stated “it was like a giant air brake deployed” and he was unable to maintain airspeed or arrest the descent. The airplane continued its descent before impacting trees and terrain. The left wing separated from the airplane before it came to rest in the trees about 12 ft off the ground. The airplane impacted trees and terrain, about 1/4- mile from the approach end of runway 09. The fuselage was substantially damaged during the accident. The right canopy frame and latch was retained and examined (figure).

Figure 1 - Actual canopy frame with connected striker pin installed and canopy parts exploded view. The canopy side frame (right side) with latch was mounted to the plexiglass canopy. In addition, there were 3 layers of foam weatherstripping layered on the bottom of the canopy frame where it joined the fuselage that created a seal when the canopy frame was closed. The latch hook, also called the striker, was mounted on the airframe. The associated operating latch mechanism was a semicircular open ended elongated notch that was spring loaded and wrapped around the striker pin when closed; it was located aft in line with the seatbacks. When the latch was in the closed and locked position, the canopy latch sprung off very easily during gentle manipulation of the trigger. The trigger was spring operated and popped off the latch on multiple attempts after slight finger pressure was applied. The latch did not have a mechanism to fully close and lock the latch from opening. The canopy frame and latch mechanism did not appear to have any irregularity or anomalous preimpact damage, appeared intact and functioned as designed. There were two latches on the airplane; only the right latch was examined. Both latches were identical in terms of their design and operation. The pilot reported that his backup latch did not hold, but no other details of the backup latch were gathered from the pilot.